Dye for photographic layers



Patented Sept. 8, i942 DYE FOR PHOTOGRAPH) LAYERS Burt H. Carroll and Jonas John Chechak, Rochester, N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., a

Jersey corporation of New- No Drawing. Application May 7,19,

' Serial No. 333,807

' 2 Claims.

This invention relates to photography and particularly to azo dyes for incorporation in photographic layers.

It is well known that dyes used in photography should remain in the layers in which they are incorporated. Many of the dyes which have been proposed for use in photographic layers either wander from the layer in which they are incorporated or if they are 'sufflciently nondifiusing bleached or removed from the layers during processing. Filter dyes, antihalation dyes and image-forming dyes, for example, should remain in the layer in which they are incorporated until it is desired to remove them during processing of the photographic element in which they are incorporated. Many dyes hitherto' used are objectionable because of the tendency to diffuse from one layer to another. Such wandering may sometimes be prevented by. precipitating the dyes with organic bases although this method of rendering the dyes non-diffusing has the disadvantage of increasing the cost of preparing the dye layers and frequently makes the incorporation of a sufiicient concentration of the dyes difficult owing to a tendency for the dye. and the precipitate to separate out in crystalsor flakes.

Azo dyes are, in generahdesirable for use in coloring photographic layers because they arerelatively light stable and may be decolorized by suitable treatment of the film. It has previously been thought that direct cotton dyes may be used to color photographic gelatin layers and that such dyes do not diil'use from the layers. However, we have found that this is not necessarily true in general.

It is, therefore, an object of the present in'ention to provide photographic layers having dyes which do not difluse through set gelatln'or which in photographic layers cannot be.

case of some naphthols inhibited by 3 or 5 subdichlorodiphenyl urea. Phenols and naphthols suitable for use in the coupling reaction are- 2-chloro-5-hydroxytoluene, p-cresol-2-sulfonic acid 01 1-naphthol-8-chloro-3,6-disulfonic acid.

with phenols or naphthols in which the position 1 para to the hydroxyl group of the phenol or naphthol is blocked so that coupling must take place ortho to the hydroxyl group.

These dyes are formed from symmetrical aro-' matic diamines containing alkyl or halogen suba phenol or a-naphthol in which the position para to the hydroxyl group is blocked 'orin the The amino naphthols may contain acyl substituents on the nitrogen of the naphthol.

branched carbon chain such as isopropyl, isobutyl and secondary or tertiary amyl. These long chain acyl groups tend to decrease diffusion of the dye. r

The dyes which we propose to use may have the following general formula:-

in which =halogen or alkyl =chemical bond -(CHz).n where 11 is a positive integer =any substituent, such as alkyl, halogen, sulfonic acid, carboxyl R. =any substituent group other than carboxyl R" and R."=hydrogen, a'substituent group, the

atoms necessary to complete a second benzene ring, which may contain sultonic acid, amino, or acylamino groups Example 1 The dye made by tetrazotizing 1 mo] 01 ortho tolidine, disul-fonic acid and coupling it in alkaline medium with 2 mols of 2-chloro-5-hydroxytoluene has the following structure:

- om cm CHQN:

Example 2 The dye made by tetrazotizing 1 mol of ortho tolidine and coupling it in an alkaline medium The acyl group maycontain a straight carbon chain or a )QrarrQ-cm Hols SOaH 1 following structure:

ample 3 The dye made by tetrazotizing 1 mol of ortho tolidine and coupling it in an --alk aline medium with 2 mols of u-naphthol-4 sulionic acid has the following structure:

OK on som 01H The dyes which we propose to use may be inconporated in filter overcoats, overcoats or interlayers in photographic films, plates or paper.

In certain cases the dyes which we propose to use may be bleached throughout in suitable alkaline bleaching solutions such as alkaline stannous chloride.

Although the specific dyes which we have described are magenta or yellow in color, we are not limited to dyes of these hues as dyes or other colors may be formed by our invention for use in photographic layers.

Dyes oi the structure which we have described are practically non-diffusing in gelatin and have no adverse effect on the sensitivity of adjacent emulsion layers. When used in filter or antihalation layers they may be discharged by the use Of sodium hydrosulfite or potassium permanganate. By forcing coupling of the tetrazotized aromatic diamine with a phenol or naphthdl ortho to the hydroxyl group oi the phenol or naphthol, dyes are produced which have sharper absorption spectra, that is which absorb more completely in one spectral region and less in other spectral regions.

- with 2 mols oi. p-phenol'sulionic acid has the.

- droxyl groups other than those ortho to the The dyes which we have proposed have high ,water solubility, thus Iacilitating the preparation or dyed layers or adequate dye density without crystallization or the dye. In general, the dyes may contain substituent groups other than those Specified above although they may not be substituted with a large number or solubilizing groups or their diilusion tendency will be increased. For example, some 01' the dyes might be made to difluse by introducing an excessive number of sulionic acid groups. This fact is well known inthe dye art and we do not intend to include within the scope of our invention dyes containing an excess number oi solubilizing groups which would increase the diffusion tendency. In general, dyes having two to foursuli'onic acids in the molecule are sufllciently soluble and do not difluse from gelatin. However, even with dyes containing more than four sulfonic acid groups the diffusion tendency may be reduced by various expedients such as acylation of amino groups or etherification 0r esterification o1. hy-

azo

group.

It is to be understood that the specific examples included herein are illustrative only and that our invention'is to be taken as limited only by the scope of the appended claims.

We claim: 7

-1. A photographic element including a light sensitive gelatino-silver halide layer and a gelatin layer containing a dye formed by tetrazotizing a symmetrical aromatic diamine having alkyl groups ortho to the amino groups and coupling it ortho to the hydroxyl-group with a phenol containing a substituent group para to its hydroxyl group.

2. A photographic element including a lightsensitive gelatino silver halide layer and adjacent thereto a gelatin filter layer containing a dye formed by tetrazotizing a symmetrical aromatic diamine havingalkyl groups ortho to the amino groups and coupling it ortho to the hydroxyl group with a phenol containing a substituent group para to its hydroxyl group.

BURT HLCARROLL. JONAS JOHN CHECHAK. 

